when 同while有何分別?

以前英文通常將when和while等通，都是用作連接兩組動作/事情的用詞。
e.g. When(While) he was working, somebody knocked at the door.
如果仔細的區分，用when和用while可以有兩種含意：
(1) when通常是連接一個時間點，while通常是連接一段時間：
e.g. When you see the light flashes, get away from here. (閃光是一個時間點)
e.g. His wallet was stolen while he was choosing a new handbag. (選擇新手包是一段時間)
(2) while可以表達出，兩個意思近乎相反或相對的片語：
e.g. She was working hard overnight while her husband went out for one-night stand. (在這裡while有轉折前後意思的作用)

WHEN係表示係1個POINT既時間..
而WHILE係一段時間..
例:
__1990*__1992__[1994_1996___1998__2000]_2002___2004_2006
____|----------|----------|----------|----------|----------|----------|----------|----------|
I am a baby when it was 3 of May 1990*
[I learn to play piano while i am 6]
希望幫到你naa=]]

Well.Refer to Longman Express2A,while is used to describe over a period of time,but when is used to describe a point of time.
That means when is shorter,and while is longer.